26 lines
1.9 KiB
Markdown
26 lines
1.9 KiB
Markdown
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# What is Application Delivery as Code?
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## The problem with PaaS
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A PaaS, or platform-as-a-service, is the glue between an application and the cloud infrastructure running it. It automates the deployment process and provides a simplified view of the underlying infrastructure, which makes developers more productive.
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However, despite the undeniable productivity benefits of using a PaaS, most applications today do not. Why? Because it's not flexible enough: each PaaS only supports certain types of application stacks and infrastructure. Applications that cannot adapt to the platform are simply not supported.
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## The problem with artisanal deploy scripts
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Most applications don't fit in any major PaaS. Instead they are deployed by a patchwork of specialized tools, usually glued together by an artisanal shell script or equivalent.
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*FIXME: example of specialized tools*
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Most teams are unhappy with their deploy script. They are high maintenance, tend to break at the worst possible time, and are less convenient to use than a PaaS. But when you need control of your stack, what other choice is there?
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## The best of both worlds: Application Delivery as Code
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Application Delivery as Code (ADC) is an alternative to PaaS and artisanal deploy scripts, which combines the best of each.
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Simply put, with ADC each application gets its own single-purpose PaaS. The platform adapts to the application, not the other way around. And because it’s defined *as code*, this custom PaaS can easily be changed over time, as the application stack and infrastructure evolves.
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Because doing this with a general programming language, like Go, would be prohibitively expensive, a good ADC implementation requires a specialized language and runtime environment. For example, Dagger uses [Cue](https://cuelang.org) as its language, and [Buildkit](https://github.com/moby/buildkit) as its runtime environment.
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